This kind of electric vehicle has left and right electric motors for individually driving left and right drive wheels, left and right brakes for individually regulating the speeds of the left and right drive wheels, and a control part for controlling the speeds of the left and right electric motors.
A travel control method of an electric vehicle in which when the brake percentages of left and right brakes operated by a driver are essentially the same the control part reads in the speeds of the left and right electric motors and reduces the speed of the electric motor at the higher speed to match it to the speed of the electric motor at the lower speed is proposed for example in JP-A-2002-142309.
Normally, in normal travel without the brakes applied, the left and right brake percentages are both zero, and the left and right brake percentages are thus the same. When at this time an influence of irregularities in the road surface causes a load to act on one of the electric motors, its speed falls and there is a possibility of the vehicle turning. However, in the control method mentioned above, because the speed of the electric motor at the higher speed is lowered to match the speed of the electric motor at the lower speed, the electric vehicle can continue to travel in a straight line.
However, on starting, when the electric vehicle shifts from a stopped state to an advancing or reversing state, if the control described above is implemented notwithstanding that the speeds of the left and right electric motors are very low, their speeds do not readily increase, and it takes time for the desired speed to be reached. And because the desired speed is generally a working speed, this means that it takes time to shift to a working state, and consequently work efficiency falls.
Thus there has been a need for the desired speed to be reached more rapidly on starting of an electric vehicle.